linux c 检测网络状态

转自：http://stackoverflow.com/questions/808560/how-to-detect-the-physical-connected-state-of-a-network-cable-connector

You want to look at the nodes in

/sys/class/net/

I experimented with mine:

Wire Plugged in:

eth0/carrier:1
eth0/operstate:unknown

Wire Removed:

eth0/carrier:0
eth0/operstate:down

Wire Plugged in Again:

eth0/operstate:up
eth0/carrier:1

GTK 程序 检测 网线是否连接 本地网络状态 C语言实现

转自：http://blog.csdn.net/a954423389/article/details/7327950

主程序创建一个进程, 每2秒查看一下网络状态,然后打印输出

通过检查文件

/sys/class/net/wlan0/operstate  (无线网络)

/sys/class/net/eth0/operstate (有线网络)

通过检查文件的内容   判断当前网络是否连接

值为up的时候,是连接 值为down的时候 是断开

1. #include <stdio.h>
2. #include <stdlib.h>
3. #include <unistd.h>
4. #include <gtk/gtk.h>
5. #include <fcntl.h>
6. #include <sys/types.h>
7. #include <sys/stat.h>
8. #define WIRELESS
9. #ifdef WIRELESS
10. #define INTERNET_STATUS_FILE "/sys/class/net/wlan0/operstate"
11. #else
12. #define INTERNET_STATUS_FILE "/sys/class/net/eth0/operstate"
13. #endif
14. #include <sys/wait.h>
15. static GtkWidget *fixed;
16. static GtkWidget *button1;
17. static GtkWidget *button2;
18. int running = 1;
19. void ring()
20. {
21. GtkWidget *window;
22. GtkWidget *table;
23. GtkWidget *button_cancel;
24. GtkWidget *label;
25. window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
26. gtk_window_set_default_size (GTK_WINDOW(window),100,100);
27. gtk_window_set_position (GTK_WINDOW(window),GTK_WIN_POS_CENTER_ALWAYS);
28. table = gtk_table_new(10,10,TRUE);
29. gtk_container_add (GTK_CONTAINER (window),table);
30. label = gtk_label_new("ring");
31. button_cancel = gtk_button_new_with_label ("quit");
32. gtk_table_attach_defaults (GTK_TABLE(table),button_cancel,2,4,7,9);
33. gtk_widget_show_all(window);
34. }
35. void www_connect_check_real ()
36. {
37. int ret = -2;
38. while (1)
39. {
40. //一定要只读模式打开,读写模式打开不可以
41. ret = open ("/sys/class/net/wlan0/operstate",O_RDONLY);
42. if (ret<0) {
43. printf("open file operstate failure%d\n",ret);
44. return;
45. }
46. char status[3]="wl\0";
47. //printf("%s",status);
48. read (ret,status,2);
49. status[3] = '\0';
50. if (0== strcmp("up",status))
51. {
52. printf("on line now \n");
53. }
54. else if (0== strcmp("do",status))
55. {
56. printf("off off \n");
57. }
58. else
59. printf("unknow error\n");
60. close (ret);
61. sleep (5);
62. }
63. }
64. int main(int argc,char* argv[])
65. {
66. GtkWidget *window,*view;
67. GtkWidget *vbox,*button,*label;
68. /*线程初始化*/
69. if (!g_thread_supported())
70. g_thread_init(NULL);
71. gdk_threads_init();
72. gtk_init(&argc,&argv);
73. window=gtk_window_new(GTK_WINDOW_TOPLEVEL);
74. gtk_window_set_title(GTK_WINDOW(window),"thread apllication");
75. vbox=gtk_vbox_new(FALSE,0);
76. gtk_container_add(GTK_CONTAINER(window),vbox);
77. label=gtk_label_new("Notice! Button is moving");
78. gtk_box_pack_start(GTK_BOX(vbox),label,FALSE,FALSE,0);
79. view=gtk_viewport_new(NULL,NULL);
80. gtk_box_pack_start(GTK_BOX(vbox),view,FALSE,FALSE,0);
81. fixed=gtk_fixed_new();
82. gtk_widget_set_usize(fixed,330,330);
83. gtk_container_add(GTK_CONTAINER(view),fixed);
84. button1=gtk_button_new_with_label("1");
85. button2=gtk_button_new_with_label("2");
86. gtk_fixed_put(GTK_FIXED(fixed),button1,10,10);
87. gtk_fixed_put(GTK_FIXED(fixed),button2,40,40);
88. GtkWidget *button_ring = gtk_button_new_with_label ("ring");
89. gtk_box_pack_start(GTK_BOX(vbox),button_ring,FALSE,FALSE,5);
90. g_signal_connect (button_ring,"clicked",G_CALLBACK(ring),NULL);
91. /*创建线程*/
92. g_thread_create((GThreadFunc)www_connect_check_real,NULL,FALSE,NULL);
93. gtk_widget_show_all(window);
94. g_signal_connect(G_OBJECT(window),"delete_event",G_CALLBACK(gtk_main_quit),NULL);
95. gtk_container_set_border_width(GTK_CONTAINER(window),10);
96. gdk_threads_enter();
97. gtk_main();
98. gdk_threads_leave();
99. return FALSE;
100. }

注意:

1,ubuntu 10.04上,当使用静态IP的时候,即使 连接着网络, 文件的值也不up 而是unknown, 这是驱动上的bug,ubuntu 11.10上就正常

http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/5.7_Technical_Notes/kernel.html

2,相关链接

http://stackoverflow.com/questions/808560/how-to-detect-the-physical-connected-state-of-a-network-cable-connector

http://www.linuxforums.org/forum/programming-scripting/142431-how-write-program-c-detect-ethernet-cable.html

3,也可以使用shell脚本来检测,网上例子很多

4,也可以编写一个内核模块来检测,后期再说,先找工作

http://stackoverflow.com/questions/7225888/how-can-i-monitor-the-nic-statusup-down-in-a-c-program-without-polling-the-ker

5,

[cpp] view plain copy

 

1. //RFC 2863操作状态
2. unsigned char       operstate;
3. /* operstate的可能取值如下：
4. enum {
5. IF_OPER_UNKNOWN,
6. IF_OPER_NOTPRESENT,
7. IF_OPER_DOWN,
8. IF_OPER_LOWERLAYERDOWN,
9. IF_OPER_TESTING,
10. IF_OPER_DORMANT,
11. IF_OPER_UP,
12. };
13. **/
14. //映射到RFC2863兼容状态的策略
15. unsigned char       link_mode;
16. /* link_mode的可能取值如下：
17. enum {
18. IF_LINK_MODE_DEFAULT,
19. IF_LINK_MODE_DORMANT,
20. };
21. **/

我们检测的文件内容,其实是这个成员变变量的值,返回值比较多,程序中只是判断了前两个字符

http://blog.csdn.net/npy_lp/article/details/7056903

linux c 检测网络状态

转自：https://blog.csdn.net/linqiongjun86/article/details/48393807

获取wifi网络状态

#include <string.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <sys/types.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

void connect_check_real ()  
{  
        int ret;  
    int fp;
    char status[10];  
        //一定要只读模式打开,读写模式打开不可以  
    ///sys/class/net/wlan0/carrier  0:down 1:up 
        fp = open ("/sys/class/net/wlan0/operstate",O_RDONLY);  
  
        if (fp<0) {  
        printf("open file operstate failure%d\n",fp);  
        return;  
        }  
        
    memset(status,0,sizeof(status));
        ret = read (fp,status,10);   
    printf("status:%s\n",status);
        if (NULL != strstr(status,"up"))  
        {  
            printf("on line now \n");  
        }  
        else if (NULL != strstr(status,"down"))  
        {  
            printf("off off \n");  
        }  
        else   
        printf("unknow error\n");  
        close (fp);      
}